A level beyond which the relative absorption of a product or service is not expected to increase. It is defined in terms of a ratio, e.g. ownership of computers per household or per hundred persons. Once the saturation point is reached, the growth of demand slows down to levels determined by population growth and replacement, although in some cases predictions of saturation points have been falsified by the emergence of multiple ownership, e.g. of cars and television sets.
Reference: The Penguin Dictionary of Economics, 3rd edt.